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Harbour water safe only on the surface

posted Oct 1, 2017, 6:00 PM by SOS SaveOceanScience   [ updated Oct 4, 2017, 6:07 PM ]
Letter to The Chronicle Herald  Sept 2017 

Reader’s Corner

 

Harbour water safe only on the surface

 

Not surprisingly, there is renewed interest in Halifax Harbor for recreational fishing and swimming (The Chronicle Herald, recent articles). Sewage and other household effluents produced by HRM residents undergo advanced primary treatment before entering the harbor.  Storm water overflows after severe rain events are not always treated.  But overall, harbor water quality appears to have improved – waters are clearer and visible surface sludge is rare. 

But a word of caution is apt. Despite earlier studies, there is no ongoing monitoring of harbor water, sediment and fish tissue(s) to ensure the safety of citizens. The data publically available for comprehensive health risk assessments of fishing and swimming are severely limited or out of date.  

Federal departments (Fisheries and Oceans, Canadian Food Inspection Agency, Health Canada, Environment and Climate Change Canada) should be conducting such monitoring and assessments but apparently do not, despite their respective responsibilities.  As well, the Province and HRM do cursory monitoring, if at all.  

Occasional single-point monitoring of fecal coliform bacteria is inadequate for meaningful health risk assessments. Water masses are highly variable in space and time, and contaminated bottom sediments sometimes mix with sub-surface waters that contact fish and swimmers.  In the absence of on-going reliable data on levels of chemical contaminants in local fish tissue (e.g., mercury, lead, plasticizers, oil constituents) and levels of water-borne pathogens (e.g., bacteria, viruses, parasites), safe conditions may be illusory.   

Hence, several actions seem prudent.  If you fish, eat what you catch sparingly, avoid bottom feeders and practise catch and release. If you swim, avoid ingesting the water, and wash well afterwards.  Most important, contact your government representatives and demand renewed comprehensive monitoring programs. Harbor waters deserve timely, evidence-based protection if fishing and swimming are to proceed safely.

 

Peter Wells

Halifax, NS.